Display device and display method

ABSTRACT

A display device displays a host vehicle and other vehicles running in driving lanes together with the driving lanes on an information display screen. When the other vehicles are present at a far region at a front side in a direction of vehicle advance outside a display range of the screen, the display device displays marks showing that the other vehicles are present at a far region at a front side in a direction of vehicle advance outside a display range of the screen at fixed positions of the driving lanes displayed on the screen.

FIELD

The present disclosure relates to a display device and display method.

BACKGROUND

In driver assistance by a driver assistance system mounted in a vehicle,it is desirable to disclose the information acquired at the vehicle sideto the driver. Japanese Unexamined Patent Publication No. 2016-182906discloses to recognize other vehicles present in surroundings of a hostvehicle and display the recognized other vehicles around an automobileicon representing the host vehicle on an information display screen (forexample, instrument panel display).

SUMMARY

If the range of recognition of the other vehicles present in thesurroundings of the host vehicle were enlarged, other vehicles presentfar away would be able to be recognized. However, even if recognizingother vehicles present far away, there is the problem that if thepositions of the other vehicles were outside the display range of theinformation display screen, the fact of the other vehicles beingrecognized could not be conveyed to the driver.

The present disclosure was made focusing on such a problem and has itsobject to enable the fact of recognition of other vehicles far awaypresent outside a display range of an information display screen to beconveyed to a driver.

To solve this problem, a display device according to one aspect of thepresent disclosure is configured to display a host vehicle and othervehicles running in driving lanes together with the driving lanes on aninformation display screen. Further, the display device is furtherconfigured to display marks showing that the other vehicles are presentin a region, that is a far region at a front side in a direction ofvehicle advance outside a display range of the information displayscreen, at fixed positions of their driving lanes displayed on theinformation display screen, when the other vehicles are present at thatregion.

Further, a display method according to another aspect of the presentdisclosure is a display method displaying a host vehicle and othervehicles running in driving lanes together with the driving lanes on aninformation display screen, comprising judging whether the othervehicles are present at a far region at a front side in a direction ofvehicle advance outside a display range of the information displayscreen and, when the other vehicles are present in that region,displaying marks showing that the other vehicles are present in thatregion at fixed positions of their driving lane displayed on theinformation display screen.

According to these aspects of the present disclosure, it is possible toconvey the fact of recognition of other vehicles far away presentoutside the display range of the information display screen to thedriver.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view of a system of a vehicle according to a firstembodiment of the present disclosure.

FIG. 2 is a view explaining operation of a distance measurement sensor.

FIG. 3 is a view showing an example of a display in a case of displayingother vehicles present in surroundings of the vehicle together with thevehicle on an information display screen.

FIG. 4 is a view showing a hardware configuration of a display deviceaccording to a first embodiment of the present disclosure.

FIG. 5 is a view showing one example of an information display screenaccording to the first embodiment of the present disclosure showingother vehicles running in a region in the front of the host vehicleoutside the display range as other-vehicle recognition marks at fixedpositions of the driving lanes.

FIG. 6 is a flow chart explaining display processing according to thefirst embodiment of the present disclosure.

FIG. 7 is a view showing one example of an information display screenaccording to a second embodiment of the present disclosure showing othervehicles running in a region in the front of the host vehicle outsidethe display range as other-vehicle recognition marks at fixed positionsof the driving lanes.

FIG. 8 is a view showing one example of an information display screenaccording to a third embodiment of the present disclosure showing othervehicles running in a region in the front of the host vehicle outsidethe display range as other-vehicle recognition marks at fixed positionsof the driving lanes.

FIG. 9A is a view showing a state where one among two other vehiclesrunning in a host vehicle driving lane in a region in the front of thehost vehicle outside the display range has changed a lane.

FIG. 9B is a view explaining a problem occurring when displaying othervehicles running in a region in the front of the host vehicle outsidethe display range as other-vehicle recognition marks at fixed positionsof the driving lanes and one among two other vehicles running in a hostvehicle driving lane in a region in the front of the host vehicleoutside the display range has changed a lane.

FIG. 10 is a flow chart explaining display processing according to afourth embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

Below, referring to the drawings, embodiments of the present disclosurewill be explained in detail. Note that, in the following explanation,similar constituent elements will be assigned the same referencenotations.

First Embodiment

FIG. 1 is a schematic view of a system of a vehicle 100 according to afirst embodiment of the present disclosure.

The vehicle 100 is provided with a camera 1, distance measurement sensor2, object recognition device 3, display device 4, and a vehicle controldevice 5. The camera 1, distance measurement sensor 2, objectrecognition device 3, display device 4, and vehicle control device 5 arerespectively connected through an internal vehicle network 6 based onthe Controller Area Network standard to be able to communicate.

The camera 1 is for example attached inside a passenger compartment ofthe vehicle 100 so as to face the region in front of the vehicle 100. Itcaptures the region in front of the vehicle 100 by a predetermined framerate (for example, 10 Hz to 40 Hz) and generate images in which thefront region is shown (below, referred to as the “camera images”).Further, each time generating a camera image, the camera 1 sends thegenerated camera image through the internal vehicle network 6 to thevehicle control device 5.

The distance measurement sensor 2 emits a plurality of laser beams orradio waves differing in emission angle horizontally and in parallel tothe distance measurement region of the surroundings of the vehicle 100as shown in (A) of FIG. 2 and receives the reflected beams of theemitted laser beams or the reflected waves of the emitted radio waves.Further, based on the received reflected beams or reflected waves, thedistance measurement sensor 2 measures the distances to roads orobstacles (for example, buildings, preceding vehicles or followingvehicles on the roads, oncoming vehicles, and other such runningvehicles, stopped vehicles, curbs, fallen objects, pedestrians, etc.)present in the distance measurement region. The distances to the roadsor obstacles, as shown in (B) of FIG. 2, are acquired for each of thereflection points (emission points) of the laser beams or radio waves.The distance measurement sensor 2 links the distances to the reflectionpoints and the coordinate information of the reflection points, thensends these as distance measurement data through the internal vehiclenetwork 6 to the object recognition device 3.

As the distance measurement sensor 2 emitting the laser beams, forexample, a LIDAR (light detection and ranging) device may be mentioned.Further, as a distance measurement sensor 2 emitting the radio waves,for example, a milliwave radar sensor may be mentioned. In the presentembodiment, as shown in (A) of FIG. 2, as the distance measurementsensor 2, a LIDAR device attached to the roof of the vehicle 100 isused.

Based on the distance measurement data, the object recognition device 3recognizes the other vehicles present in the surroundings of the vehicle100 and sends information relating to the recognized other vehicles(below, referred to as the “other-vehicle information”) through theinternal vehicle network 6 to the display device 4 and vehicle controldevice 5. Specifically, the object recognition device 3 groupsreflection points satisfying predetermined conditions among theplurality of reflection points detected based on the reflections of theemitted laser beams etc. as reflection points of the laser beamsreflected from the same objects to thereby recognize the other vehiclespresent in the surroundings of the vehicle 100. Note that in thefollowing explanation, to clearly differentiate the vehicle 100 and theother vehicles present in the surroundings of the vehicle 100,sometimes, in accordance with need, the vehicle 100 will be referred toas the “host vehicle 100”.

The display device 4 is provided with an information display screen 44(see FIG. 4) arranged at a position which a driver of the vehicle 100can see. The information display screen 44, for example, is a liquidcrystal display or organic EL display or other of various types ofdisplays. The other-vehicle information sent from the object recognitiondevice 3 includes identification information of the other vehicles (IDnumbers assigned to the vehicles at the time of recognition etc.), typeinformation of the other vehicles (passenger cars or trucks,motorcycles, etc.), position information of the other vehicles whenbased on the vehicle 100 (relative position information), the presenceof any other vehicles running in front of the vehicle 100 and in thesame lane as the vehicle 100 (below, referred to as “precedingvehicles”), preceding vehicle information relating to thevehicle-vehicle distance from the preceding vehicles, etc. Based on thisother-vehicle information, the display device 4 according to the presentembodiment, for example, as shown in FIG. 3, displays the other vehiclespresent in the surroundings of the vehicle 100 together with the vehicle100 on the information display screen 44. Specifically, as shown in FIG.3, if the other vehicles are passenger cars, the display device 4displays predetermined passenger car-use icons at the relative positionsof the other vehicles. In the same way, if the other vehicles aretrucks, it displays predetermined truck -use icons at the relativepositions of the other vehicles. While not shown, if the other vehiclesare motorcycles, it displays predetermined motorcycle-use icons at therelative positions of the other vehicles.

The vehicle control device 5 receives as input, in addition theabove-mentioned camera images and other-vehicle information, varioustypes of information (for example, information on appearance of driver,current position information of the vehicle 100, vehicle speedinformation, etc.) required for performing various types of driverassistance for automatically performing part or all of the drivingoperations relating to acceleration, steering, and braking. Further, thevehicle control device 5 prepares a driving plan of the vehicle 100based on these information and automatically performs part or all of thedriving operations relating to acceleration, steering, and braking inaccordance with this driving plan. Note that, “acceleration, steering,and braking” may, for example, also be read as “acceleration,deceleration, and turning” or “driving, braking, and steering” etc.

FIG. 4 is a view showing the hardware configuration of the displaydevice 4.

As shown in FIG. 4, the display device 4 is provided with acommunication interface 41, storage part 42, processing part 43, andinformation display screen 44.

The communication interface 41 is provided with an interface circuit forconnecting the display device 4 to the internal vehicle network 6. Thatis, the communication interface 41 is connected through the internalvehicle network 6 to the object recognition device 3. The communicationinterface 41 transfers the received other-vehicle information to theprocessing part 43 each time receiving other-vehicle information fromthe object recognition device 3.

The storage part 42 has a HDD (hard disk drive) or optical recordingmedium, semiconductor memory, or other storage medium and stores varioustypes of computer programs or data etc. used for processing at theprocessing part 43.

The processing part 43 has one or more processors and their peripheralcircuits. The processing part 43 runs the various types of computerprograms stored at the storage part 42 and comprehensively controls theoverall operation of the display device 4 and is, for example, a CPU(central processing unit). Based on the other-vehicle informationreceived through the communication interface 41, the processing part 43executes display processing for displaying the other vehicles present inthe surroundings of the vehicle 100 on the information display screen44. Details of this display processing will be explained later whilereferring to FIG. 5.

The information display screen 44, as explained above, for example, is aliquid crystal display or organic EL display or other of various typesof displays which is arranged at a position which the driver of thevehicle 100 can see and which displays information (for example, textinformation or image information) in accordance with signals output fromthe processing part 43.

Note that the hardware configurations of the object recognition device 3and vehicle control device 5 are not shown, but in the same way as thedisplay device 4, they are provided with communication interfaces,storage parts, and processing parts.

Here, in the driver assistance by the vehicle control device 5,information acquired at the vehicle side is shown to the driver toconvey to the driver whether the information acquired at the vehicleside is accurate etc. Therefore, in the present embodiment, as shown inFIG. 3, the other vehicles present in the surroundings of the vehicle100 acquired at the vehicle side, that is, the other vehicles present inthe surroundings of the vehicle 100 recognized by the object recognitiondevice 3, is made to be displayed by the display device 4 at theinformation display screen 44.

At this time, if the range of recognition of other vehicles by theobject recognition device 3 were enlarged, other vehicles present faraway could also be recognized. However, if trying to make all recognizedother vehicles be displayed on the information display screen 44, itwould be necessary to reduce the scale the more the range of recognitionof the other vehicles were enlarged. As a result, there is the problemthat the displays of the other vehicles would become smaller and harderto see.

On the other hand, if maintaining as is the scale at a suitable scale ofthe same extent as up to now, there is the problem that even ifrecognizing other vehicles present far away in the front, if thepositions of the other vehicles were outside the display range of theinformation display screen 44, the other vehicles could not be displayedat the information display screen 44 and therefore the fact ofrecognition of other vehicles present far away in the front could not beconveyed to the driver. For example, if displaying other vehiclespresent in a region up to 100 meters in front of the host vehicle 100 onthe information display screen 44, when recognizing another vehiclepresent at a position 150 meters in the front, that other vehiclepresent at a position 150 meters in the front would be another vehiclepositioned outside the display range of the information display screen44 and that other vehicle could no longer be displayed at theinformation display screen 44.

Therefore, in the present embodiment, when recognizing another vehiclerunning in a region in front of the host vehicle 100 outside the displayrange of the information display screen 44 (below, referred to as a“region in the front of the host vehicle outside the display range”), asshown in FIG. 5, it was decided to display a predetermined other-vehiclerecognition mark 200 showing that another vehicle has been recognized ata fixed position of the driving lane at which that other vehicle isrunning, for example, at the end part of the front side in the directionof vehicle advance. Note that, in the present embodiment, theother-vehicle recognition mark 200, as shown in FIG. 5, is made avehicle icon similar to the host vehicle 100 etc., but the disclosure isnot limited to this. For example, a simple symbol, word, etc. may alsobe made the other-vehicle recognition mark 200.

In this way, when recognizing another vehicle running in the region inthe front of the host vehicle outside the display range, by displayingthe other-vehicle recognition mark 200 at a fixed position of thedriving lane in which that other vehicle is running (the end part of thefront side in the direction of vehicle advance), it is possible tomaintain a suitable scale and secure ease of viewing of the screen whileconveying the fact of recognition of another vehicle present far away tothe driver.

Note that, in the example shown in FIG. 5, other-vehicle marks 200 aredisplayed in the driving lane in which the host vehicle 100 is running(below, referred to as the “host vehicle driving lane”) and the left andright adjacent driving lanes adjacent to the host vehicle driving lane,so this means there are other vehicles running at the host vehicledriving lane and left and right adjacent driving lanes outside thedisplay range of the information display screen 44.

FIG. 6 is a flow chart explaining details of the display processingaccording to the present embodiment performed at the processing part 43of the display device 4. The display device 4 executes the presentroutine every time receiving other-vehicle information from the objectrecognition device 3.

At step S1, the display device 4 judges if there are other vehiclesrunning in the region in the front of the host vehicle outside thedisplay range based on the relative position information of the othervehicles present in the surroundings of the host vehicle included in theother-vehicle information. If there are other vehicles running in theregion in the front of the host vehicle outside the display range, thedisplay device 4 proceeds to the processing of step S2. On the otherhand, if there are no other vehicles running in the region in the frontof the host vehicle outside the display range, the display device 4proceeds to the processing of step S3.

Note that in the present embodiment, the region up to 100 meters infront of host vehicle 100 is inside the display range of the informationdisplay screen 44, so the region from 100 meters in front of the hostvehicle 100 to the recognition limit of the object recognition device 3(for example, 150 meters in front of the host vehicle 100) becomes theregion in the front of the host vehicle outside the display range.Below, the region in front of the host vehicle 100 inside the displayrange of the information display screen 44 will be differentiated fromthe region in the front of the host vehicle outside the display range byreferring to it as the “region in front of the host vehicle inside thedisplay range”.

At step S2, the display device 4 displays the other vehicles present inthe region in front of the host vehicle inside the display range and theother-vehicle recognition marks 200 on the information display screen44. Specifically, the display device 4 displays other vehicles at therelative positions of the other vehicles present in the region in frontof the host vehicle inside the display range and displays other-vehiclerecognition marks 200 at fixed positions of the driving lanes of theother vehicles running at the region outside the display range (in thepresent embodiment, the end parts at the front side in the direction ofvehicle advance).

Note that in the present embodiment, the other-vehicle recognition marks200 are made vehicle icons, so to keep from giving the driver an oddfeeling as much as possible, the vehicle icons are displayed at fixedpositions of the driving lanes so that their center points arepositioned on the lane center lines of the driving lanes. Further, thevehicle icons are displayed at fixed positions of the driving lanes sothat their orientations match the orientations of tangents of the lanecenter lines of the driving lanes.

Further, in the present embodiment, the fixed positions of the drivinglanes (the end parts at the front side in the direction of vehicleadvance) are made points on the driving lanes forming the boundary ofthe region in front of the host vehicle inside the display range andregion outside the display range (point 100 meters in front of the hostvehicle 100).

At step S3, the display device 4 displays the other vehicles present inthe region in front of the host vehicle inside the display range on theinformation display screen 44. Specifically, the display device 4displays that other vehicles at the relative positions of the othervehicles present in the region in front of the host vehicle inside thedisplay range.

The display device 4 according to the present embodiment explained aboveis configured to display the host vehicle 100 and other vehicles runningin the driving lanes on the information display screen 44 together withthe driving lanes. Furthermore, the display device 4 is configured sothat when other vehicles are present in a far region at the front sidein the direction of vehicle advance outside the display range of theinformation display screen 44 (that is, region in the front of the hostvehicle outside the display range), it displays the other-vehiclerecognition marks 200 (in the present embodiment, the vehicle icons) atfixed positions of the driving lanes displayed on the informationdisplay screen 44 (in the present embodiment, the end parts at the frontside in the direction of vehicle advance of the driving lanes).

Due to this, other vehicles running in a nearby region inside of thedisplay range of the information display screen 44 can be displayed onthe information display screen 44 while maintaining a suitable scale andsecuring ease of viewing of the screen. Further, other vehicles runningin a far away region outside the display range of the informationdisplay screen 44 can be displayed as other-vehicle recognition marks200 at the end parts at the front side in the direction of vehicleadvance of the driving lanes in which the other vehicles are running, sothe fact of recognition of other vehicles present far away can beconveyed to the driver.

Note that the present embodiment, if changing the way of viewing it, canbe grasped as a display method displaying the host vehicle 100 and othervehicles running in the driving lanes on the information display screen44 together with the driving lanes. Specifically, it can be grasped as adisplay method comprising judging whether other vehicles are present ata far region at a front side in a direction of vehicle advance outside adisplay range of the information display screen 44 and, when othervehicles are present in that region, displaying other-vehiclerecognition marks 200 showing that the other vehicles are present inthat region at fixed positions of their driving lanes displayed on theinformation display screen 44.

Second Embodiment

Next, a second embodiment of the present disclosure will be explained.The present embodiment differs from the first embodiment on the point ofdisplaying the other-vehicle recognition mark 200 only at the hostvehicle driving lane. Below, this point of difference will be focused onin the explanation.

In the above-mentioned first embodiment, as shown in FIG. 5, if therewere other vehicles in the driving lanes at the region outside thedisplay range of the information display screen 44, other-vehiclerecognition marks 200 would be displayed at the end parts at the frontside in the direction of vehicle advance of all of the driving lanes.This being so, as shown in FIG. 5, the other-vehicle recognition marks200 would be displayed in a single horizontal line at the end parts atthe front side in the direction of vehicle advance of the driving lanes.

Other vehicles running on driving lanes at the region outside thedisplay range of the information display screen 44 actually almost neverare running in a single horizontal line. For this reason, if ending updisplaying the other-vehicle recognition marks 200 at the end parts atthe front side in the direction of vehicle advance of the driving lanesin a single horizontal line, an odd feeling is liable to be given to thedriver.

Therefore, in the present embodiment, as shown in FIG. 7, it was decidedthat only where there was another vehicle running in the host vehicledriving lane at the region outside the display range of the informationdisplay screen 44 would an other-vehicle recognition mark 200 bedisplayed at the end part at the front side in the direction of vehicleadvance of the host vehicle driving lane. In other words, it was decidedthat even when there was another vehicle in a driving lane other thanthe host vehicle driving lane in the region outside the display range ofthe information display screen 44, an other-vehicle recognition mark 200would not be displayed at the driving lane in which that other vehiclewas running.

Due to this, it is possible to prevent other-vehicle recognition marks200 from ending up being displayed in a single horizontal line at theend parts at the front side in the direction of vehicle advance of thedriving lanes, so it is possible to prevent giving the driver an oddfeeling.

Third Embodiment

Next, a third embodiment of the present disclosure will be explained.The present embodiment differs from the first embodiment on the point ofmaking the display range at the front side in the direction of vehicleadvance of the host vehicle driving lane longer than the display rangesat the front side in the direction of vehicle advance of the drivinglanes other than the host vehicle driving lanes. Below, this point ofdifference will be focused on in the explanation.

As explained above, as shown in FIG. 5, if ending up displayingother-vehicle recognition marks 200 in a horizontal single line at fixedpositions of the driving lanes (the end parts at the front side in thedirection of vehicle advance), the driver is liable to be given an oddfeeling. Therefore, in the present embodiment, as shown in FIG. 8, thedisplay range at the front side in the direction of vehicle advance ofthe host vehicle driving lane was made longer than the display ranges atthe front side in the direction of vehicle advance of the driving lanesother than the host vehicle driving lanes.

Due to this, it is possible to make the fixed position of the hostvehicle driving lane (the end part at the front side in the direction ofvehicle advance) and the fixed positions of the adjacent driving lanesbesides the host vehicle driving lane (the end parts at the front sidein the direction of vehicle advance) different (the fixed position ofthe host vehicle driving lane becomes positioned further than the fixedpositions of the adjacent driving lanes), so even if displayingother-vehicle recognition marks 200 at the end parts at the front sidein the direction of vehicle advance of all of the driving lanes, it ispossible to prevent the other-vehicle recognition marks 200 from beingaligned in a single horizontal line. Therefore, it is possible to keepthe driver from being given an odd feeling.

Note that, it is also possible to make the display range at the frontside in the direction of vehicle advance of the host vehicle drivinglane longer than the display ranges at the front side in the directionof vehicle advance of the driving lanes besides the host vehicle drivinglane while, like in the above-mentioned second embodiment, displayingthe other-vehicle recognition mark 200 only at the host vehicle drivinglane.

Fourth Embodiment

Next, a fourth embodiment of the present disclosure will be explained.The present embodiment differs from the first embodiment on the pointthat when another vehicle which had been displayed at a fixed positionof the driving lane has been switched with another vehicle, theother-vehicle recognition mark 200 is erased for a certain time or madeto flash, then made to be redisplayed.

FIG. 9A is a view showing a state where one among two other vehicles101, 102 running in the host vehicle driving lane in a region in thefront of the host vehicle outside the display range has changed a lane.FIG. 9B is a view explaining a problem occurring when displaying othervehicles running in a region in the front of the host vehicle outsidethe display range as other-vehicle recognition marks at fixed positionsof the driving lanes and one among two other vehicles running in thehost vehicle driving lane in a region in the front of the host vehicleoutside the display range has changed a lane.

In the above-mentioned first embodiment, for example, as shown in FIG.9A, when two other vehicles 101, 102 are running in the host vehicledriving lane in a region in the front of the host vehicle outside thedisplay range, even when the other vehicle 101 at the near side whenviewed from the host vehicle 100 changes lanes to move to an adjacentdriving lane, the other vehicle 102 at the far side when viewed from thehost vehicle 100 is running in the host vehicle driving lane, so asshown in FIG. 9B, an other-vehicle recognition mark 200 continues to bedisplayed at a fixed position of the host vehicle driving lane (the endpart at the front side in the direction of vehicle advance). The displayof the other-vehicle recognition mark 200 at the host vehicle drivinglane does not change before and after the lane change of the othervehicle 101.

For this reason, the fact of the other vehicle 101 which had beendisplayed at a fixed position of the host vehicle driving lane (the endpart at the front side in the direction of vehicle advance) beingswitched with another vehicle 102 could not be conveyed to the driver.

Therefore, in the present embodiment, when another vehicle which hadbeen displayed at a fixed position of the driving lane is switched withanother vehicle, it was decided to erase the other-vehicle recognitionmark 200 which had been displayed at the fixed positions for a certaintime or make it flash, then redisplay them.

Due to this, when another vehicle which had been displayed at a fixedposition of the driving lane in the region in the front of the hostvehicle outside the display range is switched with another vehicle, itis possible to convey the switch to the driver.

FIG. 10 is a flow chart explaining details of the display processingaccording to the present embodiment performed during the display of theother-vehicle recognition marks 200 in the processing part 43 of thedisplay device 4. The display device 4 performs the present routine eachtime receiving other-vehicle information from the object recognitiondevice 3.

At step S11, the display device 4 judges based on the identificationinformation (ID numbers) of other vehicles contained in theother-vehicle information acquired from the object recognition device 3whether another vehicle which had been displayed at a fixed position ofthe driving lane (the end part at the front side in the direction ofvehicle advance) has been switched with another vehicle. Specifically,if among the other vehicles running in the region in the front of thehost vehicle outside the display range of the host vehicle driving lane,the ID number of the other vehicle closest in distance with the hostvehicle 100 differs from the time of the previous processing, thedisplay device 4 judges that the other vehicle which had been displayedat the fixed position of the host vehicle driving lane (the end part ofat the front side in the direction of vehicle advance) had been switchedwith another vehicle. For driving lanes besides the host vehicle drivinglane, the presence of any switch is similarly judged.

If the other vehicle which had been displayed at a fixed position of thedriving lane (the end part at the front side in the direction of vehicleadvance) has been switched with another vehicle, the display device 4proceeds to the processing of step S12. On the other hand, if the othervehicle which had been displayed at a fixed position of the driving lane(the end part at the front side in the direction of vehicle advance) hasnot been switched with another vehicle, the display device 4 ends thecurrent processing.

At step S12, the display device 4 erases for a certain time the displayof the other-vehicle recognition mark 200 which had been displayed at afixed position of the driving lane or makes it flash when there was aswitch, then redisplays it.

In this way, according to present embodiment, the display device 4 isconfigured so that when another vehicle with the shortest distance fromthe host vehicle 100 in each driving lane in a region in the front ofthe host vehicle outside the display range is switched with anothervehicle, it erases the display of the other-vehicle recognition mark fora certain time or makes it flash, then redisplays it.

Due to this, when another vehicle which had been displayed at a fixedposition of a driving lane is switched with another vehicle in a regionin the front of the host vehicle outside the display range, that switchcan be conveyed to the driver.

Above, embodiments of the present disclosure were explained, but theabove embodiments only show part of the examples of application of thepresent disclosure and are not intended to limit the technical scope ofthe present disclosure to the specific configurations of theembodiments.

For example, in the above embodiments, when there is another vehicle ina region at the front side of the host vehicle 100 in the direction ofvehicle advance inside the display range of the information displayscreen 44, even if there is another vehicle in the region in the frontof the host vehicle outside the display range, it is also possible notto display the other-vehicle recognition mark 200. This is because instate where another vehicle which is running in the host vehicle drivinglane and which the host vehicle 100 is following or another vehiclewhich is running in an adjacent driving lane and which is projected tohave an effect on the driving of the host vehicle 100 is displayed onthe information display screen 44, it is considered that there may be noneed to necessarily display another vehicle present in a region in thefront of the host vehicle outside the display range with less effectthan these other vehicles.

1. A display device configured to display a host vehicle and othervehicles running in driving lanes together with the driving lanes on aninformation display screen, wherein the display device is configured todisplay marks showing that the other vehicles are present in a region,that is a far region at a front side in a direction of vehicle advanceoutside a display range of the information display screen, at fixedpositions of their driving lanes displayed on the information displayscreen, when the other vehicles are present at that region.
 2. Thedisplay device according to claim 1, wherein the fixed positions are endparts at the front side in the direction of vehicle advance of thedriving lanes, and the marks are vehicle icons.
 3. The display deviceaccording to claim 2, further configured so as to display the marks onlyin a host vehicle driving lane in which the host vehicle is runningamong the driving lanes.
 4. The display device according to claim 2,further configured so as to make the display range at the front side inthe direction of vehicle advance of a host vehicle driving lane in whichthe host vehicle is running longer than the display range at the frontside in the direction of vehicle advance of an adjacent driving laneadjacent to the host vehicle driving lane.
 5. The display deviceaccording to claim 1, further configured so that when another vehicleclosest in distance from the host vehicle on a driving lane present inthe region has been switched with another vehicle, it erases the displayof the mark for a certain time or makes it flash, then redisplays it. 6.The display device according to claim 1, further configured so that whenother vehicles are present in a region at the front side in thedirection of vehicle advance of the host vehicle inside the displayrange of the information display screen, it does not display the marks.7. A display method displaying a host vehicle and other vehicles runningin driving lanes together with the driving lanes on an informationdisplay screen, the display method comprising judging whether the othervehicles are present at a far region at a front side in a direction ofvehicle advance outside a display range of the information displayscreen and, when the other vehicles are present in that region,displaying marks showing that the other vehicles are present in thatregion at fixed positions of their driving lane displayed on theinformation display screen.